Generally, the antilock-braking system (ABS) of a vehicle provides a rapid intermittent hydraulic brake pressure to each wheel for averting wheel lockup by detecting the variation of wheel rotations during braking.
The pump generating the rapid intermittent hydraulic brake pressure is primarily a piston pump installed at the ABS modulator. A cam rotating via a motor repeatedly presses a piston, resiliently supported by a spring, in a short time period interval to thereby generate the intermittent hydraulic pressure.